The present invention relates to scintillator fabrication methods and scintillators. More specifically, the present invention provides a variety of scintillators, including strontium halide scintillators, calcium halide scintillators, cerium halide scintillators and cesium barium halide scintillators. Related devices and methods of using the scintillators described herein are also provided.
Scintillation spectrometers are widely used in detection and spectroscopy of energetic photons (e.g., X-rays and g-rays). Such detectors are commonly used, for example, in nuclear and particle physics research, medical imaging, diffraction, non-destructive testing, nuclear treaty verification and safeguards, nuclear non-proliferation monitoring, and geological exploration.
Important requirements for the scintillation materials used in these applications include high light output, transparency to the light it produces, high stopping efficiency, fast response, good proportionality, low cost and availability in large volume. These requirements are often not met by many of the commercially available scintillators. While general classes of chemical compositions may be identified as potentially having some attractive scintillation characteristic(s), specific compositions/formulations and structures having both scintillation characteristics and physical properties necessary for actual use in scintillation spectrometers and various practical applications, as well as capability of imaging at a high resolution, have proven difficult to predict or produce. Specific scintillation properties are not necessarily predictable from chemical composition alone, and preparing effective scintillators from even candidate materials often proves difficult. For example, while the composition of sodium chloride had been known for many years, the invention by Hofstadter of a high light-yield and conversion efficiency scintillator from sodium iodide doped with thallium launched the era of modern radiation spectrometry. More than half a century later, thallium doped sodium iodide, in fact, still remains one of the most widely used scintillator materials. Since the invention of NaI(Tl) scintillators in the 1940's, for half a century radiation detection applications have depended to a significant extent on this material. As the methodology of scintillator development evolved, new materials have been added, and yet, specific applications, particularly those requiring high resolution imaging and large volumes, are still hampered by the lack of scintillators suitable for particular applications.
As a result, there is continued interest in the search for new scintillator formulations and physical structures with both the enhanced performance and the physical characteristics needed for use in various applications. Today, the development of new scintillators continues to be as much an art as a science, since the composition of a given material does not necessarily determine its performance and structural properties as a scintillator, which are strongly influenced by the history (e.g., fabrication process) of the material as it is formed. While it is may be possible to reject a potential scintillator for a specific application based solely on composition, it is not possible to predict whether a material with promising composition will produce a scintillator with the desired properties.
Thus, a need exists for scintillators that have imaging capability with improved properties, such as spatial and/or temporal resolution, and methods of making the scintillators.